Integral membrane proteins of the nuclear envelope interact with lamins and chromosomes, and binding is modulated by mitotic phosphorylation

Cell. 1993 Jul 2;73(7):1267-79. doi: 10.1016/0092-8674(93)90355-t.


Lamina-associated polypeptides (LAPs) 1A, 1B, 1C, and 2 are integral membrane proteins of the nuclear envelope associated with the nuclear lamina. Using in vitro assays, we show that LAPs 1A and 1B specifically bind to both lamins A and C and lamin B1, while LAP 2 associates only with lamin B1. LAP 2 also binds to mitotic chromosomes. The LAPs are phosphorylated during mitosis, and phosphorylation of LAP 2 by mitotic cytosol inhibits its binding to both lamin B1 and chromosomes. During late anaphase, LAP 2 associates with chromosomes prior to assembly of most lamins. Together, these data suggest that LAP 2 may have a key role in initial events of nuclear envelope reassembly, and that both LAP 2 and LAP 1 may be involved in attaching lamins to the nuclear envelope.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding Sites
  • CHO Cells
  • Chromosomes
  • Cricetinae
  • Lamin Type B*
  • Lamins
  • Liver / metabolism
  • Membrane Proteins / analysis
  • Membrane Proteins / metabolism*
  • Microsomes / metabolism
  • Mitosis
  • Nuclear Envelope / metabolism*
  • Nuclear Proteins / metabolism*
  • Phosphorylation
  • Rats


  • Lamin Type B
  • Lamins
  • Membrane Proteins
  • Nuclear Proteins